Module: Jekyll::Utils::WinTZ

Extended by:
WinTZ
Included in:
WinTZ
Defined in:
lib/jekyll/utils/win_tz.rb

Instance Method Summary collapse

Instance Method Details

#calculate(timezone, now = Time.now) ⇒ Object

Public: Calculate the Timezone for Windows when the config file has a defined

'timezone' key.

timezone - the IANA Time Zone specified in “_config.yml”

Returns a string that ultimately re-defines ENV in Windows



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# File 'lib/jekyll/utils/win_tz.rb', line 14

def calculate(timezone, now = Time.now)
  External.require_with_graceful_fail("tzinfo") unless defined?(TZInfo)
  tz = TZInfo::Timezone.get(timezone)

  #
  # Use period_for_utc and utc_total_offset instead of
  # period_for and observed_utc_offset for compatibility with tzinfo v1.
  offset = tz.period_for_utc(now.getutc).utc_total_offset

  #
  # POSIX style definition reverses the offset sign.
  #   e.g. Eastern Standard Time (EST) that is 5Hrs. to the 'west' of Prime Meridian
  #   is denoted as:
  #     EST+5 (or) EST+05:00
  # Reference: https://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html
  sign = offset.positive? ? "-" : "+"

  rational_hours = offset.abs.to_r / 3600
  hours = rational_hours.to_i
  minutes = ((rational_hours - hours) * 60).to_i

  #
  # Format the hours and minutes as two-digit numbers.
  time = format("%<hours>02d:%<minutes>02d", :hours => hours, :minutes => minutes)

  Jekyll.logger.debug "Timezone:", "#{timezone} #{sign}#{time}"
  #
  # Note: The 3-letter-word below doesn't have a particular significance.
  "WTZ#{sign}#{time}"
end